The original European Patent Office (EPO) was constructed in 1972 in the Austrian capital. Having reached the end of its service life, a decision was made against demolition in favour of comprehensive renovation. ATP won the competition bid for the project in 2021, and in the years since has transformed it into a “Green Hub” that has achieved the highest ever BREEAM rating in the DACH region—a credit to its net-zero lifecycle goal and its aim to reach carbon neutrality by 2030.
Located between the UNESCO listed Belvedere Palace, the Salesian Convent and the Botanical Gardens, the design had to navigate the city’s rich architectural traditions alongside its thoroughly contemporary aims. The goal of the renovation was ambitious: to create a carbon neutral, modern, light-filled office building. As the architects explain: “We stripped the building down to its structural framework, redesigned the vertical access and renewed the facade both aesthetically and in terms of energy performance. The building services were also modernised and aligned with the goal of achieving net-zero emissions.”
A flexible program and pavilion-like design
Designed like a pavilion, the Green Hub’s most significant new design element is an atrium that connects the varying programs and levels of the building. The ground floor remains a public area, while communal facilities—the cafeteria, servery and event spaces—have been relocated to the top floor. The levels between house office spaces designed to be flexible and open. The rooms can be easily adapted in width and depth to meet changing user needs, all without major structural modifications.
Adaptive reuse and sustainable materials lower carbon cost
By retaining the existing reinforced concrete structure, the renovation reduced embodied carbon by approximately 55% compared to a complete rebuild, saving roughly 1,089 tonnes of carbon. The new construction utilised Holcim ECOPact low-carbon concrete, which alone contributed a 38% reduction in concrete-related emissions. The thermal efficiency of the new HQ has been enhanced through Isoguard™ AK PIR insulation boards, while a locally sourced Austrian larch timber facade and acoustic climate panels improve energy performance and indoor comfort.
Record-breaking BREEAM certification driven by renewables
The building is powered by renewable energy, supplied by photovoltaic panels on the roof and facade and ground-source geothermal probes are used for heating and cooling. Additional measures, including ecological rainwater management and the use of recycled materials, further minimise environmental impact, collectively enabling the building to achieve BREEAM “Outstanding” certification with a score of 98.47%—the highest rating achieved in the DACH region to date.
